Articles 2020

Les récifs coralliens ont franchi un "point de basculement" climatique

It looked like snow under water: white, endless, and still. The reef, my friend Lisbeth said, was “the most beautiful thing she’d ever seen.” For a second, I almost agreed. Then, I stared at it for a long time before replying. She wasn’t wrong about its beauty. But she was also showing me death. Bleached coral isn’t a kind of coral. It’s the moment just after the funeral, what’s left when life is gone. A cathedral of bone-white skeletons stretching over an empire of calcified death. From above, it glows like marble. Up close, it’s a graveyard.

L’humanité a trop déstabilisé le climat, au point de l’avoir rapproché de « points de bascule » au potentiel cataclysmique, alertent 160 scientifiques dans un nouveau rapport.

Unless global heating is reduced to 1.2C ‘as fast as possible’, warm water coral reefs will not remain ‘at any meaningful scale’, a report by 160 scientists from 23 countries warns

Economic assumptions about risks of the climate crisis are no longer relevant, says the communications expert Genevieve Guenther

The world has been too optimistic about the risk to humanity and planet – but devastation can still be avoided, says Timothy Lenton

Despite working on polar science for the British Antarctic Survey for 20 years, Louise Sime finds the magnitude of potential sea-level rise hard to comprehend

The planet is edging close to irreversible change, according to the most comprehensive probability analysis yet of climate “tipping points.”

Tipping elements within the Earth system are increasingly well understood. Scientists have identified more than 25 parts of the Earth’s climate system that are likely to have “tipping points” – thresholds where a small additional change in global warming will cause them to irreversibly shift into a new state. The “tipping” of these systems – which include the Atlantic Meridional Overturning Circulation (AMOC), the Amazon rainforest and the Greenland ice sheet – would have profound consequences for both the biosphere and people. More recent research suggests that triggering one tipping element could cause subsequent changes in other tipping elements, potentially leading to a “tipping cascade”. For example, a collapsed AMOC could lead to dieback of the Amazon rainforest and hasten the melt of the Greenland ice sheet.

Lenton, the founding director of the Global Systems Institute at the University of Exeter, was the lead author of the 2008 paper that formally introduced the idea of tipping points in the Earth’s climate system.

Thousands of Greenland's crystal-clear blue lakes have turned a murky brown thanks to global warming — and the worst part is that they've started emitting carbon dioxide. Record heat and rain in 2022 pushed the lakes of West Greenland past a tipping point, so rather than absorbing carbon dioxide (CO₂), they began to emit it into the atmosphere, according to a new study.

De metafoor van het 'tipping point' of 'kantelpunt' is contraproductief in de context van de klimaatopwarming, argumenteert een groep wetenschappers in het vakblad Nature. Het concept kan mensen in verwarring brengen en actie in de weg staan, denken de onderzoekers.

Oceanographer Stefan Rahmstorf explains why Amoc breakdown could be catastrophic for both humans and marine life

Small increase in temperature of intruding water could lead to very big increase in loss of ice, scientists say

An international team of scientists has warned against relying on nature providing straightforward 'early warning' indicators of a climate disaster, as new mathematical modeling shows new fascinating aspects of the complexity of the dynamics of climate. It suggests that the climate system could be more unpredictable than previously thought.

Scientists now have a better understanding of the risks ahead and a new early warning signal to watch for.

Collapse in system of currents that helps regulate global climate would be at such speed that adaptation would be impossible

Cruciale kantelpunten in het klimaatsysteem van de aarde komen in sneltempo dichterbij. Dat blijkt uit het grootste onderzoek ooit naar “tipping points”. Meer dan tweehonderd wetenschappers werkten mee aan een tekst met waarschuwingen en aanbevelingen, die is gepresenteerd op de klimaattop in Dubai (COP28).

Humanity faces ‘devastating domino effects’ including mass displacement and financial ruin as planet warms

Extreme milieufenomenen zoals bosbranden en droogtes zetten ecosystemen zodanig onder druk dat ze steeds moeilijker terug evenwicht vinden. Dat leidt dan tot een zogeheten tipping point voor ecologisch verval. En die kantelpunten komen steeds sneller, zegt een nieuwe studie in Nature.

Amazon rainforest and other ecosystems could collapse ‘very soon’, researchers warn

Vast releases of gas, along with future ‘methane bombs’, represent huge threat – but curbing emissions would rapidly reduce global heating

By replacing thousands of equations with just one, ecology modelers can more accurately assess how close fragile environments are to a disastrous “tipping point.”

Three “super-tipping points” for climate action could trigger a cascade of decarbonisation across the global economy, according to a report. Relatively small policy interventions on electric cars, plant-based alternatives to meat and green fertilisers would lead to unstoppable growth in those sectors, the experts said. But the boost this would give to battery and hydrogen production would mean crucial knock-on benefits for other sectors including energy storage and aviation.

Le rythme actuel de réchauffement pourrait déclencher plusieurs « points de bascule » planétaires : des changements abrupts et irréversibles du système climatique. Les chercheurs Aurélien Boutaud et Natacha Gondran nous expliquent pourquoi.

A recent paper suggested damaging climate tipping points could be closer than first thought.

Governments and businesses failing to change fast enough, says United in Science report, as weather gets increasingly extreme. Despite intensifying warnings in recent years, governments and businesses have not been changing fast enough, according to the United in Science report published on Tuesday. The consequences are already being seen in increasingly extreme weather around the world, and we are in danger of provoking “tipping points” in the climate system that will mean more rapid and in some cases irreversible shifts.

Giant ice sheets, ocean currents and permafrost regions may already have passed point of irreversible change

As Nobel laureate Solow said to Congress when criticizingeconomicmodelsforfailingtoanticipatethe“GreatReces-sion,” “Every proposition has to pass a smell test: Does itreally make sense?” (2). The methods and conclusions inDietzetal.(1)donotmakesense. ...

Anthropogenic activities are increasingly affecting ecosystems across the globe. Meanwhile, empirical and theoretical evidence suggest that natural systems can exhibit abrupt collapses in response to incremental increases in the stressors, sometimes with dramatic ecological and economic consequences. These catastrophic shifts are faster and larger than expected from the changes in the stressors and happen once a tipping point is crossed.

Climate tipping points in the Antarctica, the Arctic and the Amazon are at risk of being reached before or at the current level of global warming of 1.2 degrees Celsius, requiring a “major rethink” of global climate goals and the action necessary to achieve them, according to a recent report.

More than three-quarters of the world's largest rainforest has become less resilient to drought since the early 2000s, with areas near humans and with lower rainfall being the worst hit

Five times in the last 500m years, more than three-fourths of marine animal species perished in mass extinctions. Each of these events is associated with a major disruption of Earth’s carbon cycle. How such catastrophes occur remains mysterious. But recent research increasingly points to the possibility that the Earth system – that is, life and the environment – may experience a cascade of disruptions when stressed beyond a tipping point.

If there’s one thing we know about climate breakdown, it’s that it will not be linear, smooth or gradual. Just as one continental plate might push beneath another in sudden fits and starts, causing periodic earthquakes and tsunamis, our atmospheric systems will absorb the stress for a while, then suddenly shift. Yet, everywhere, the programmes designed to avert it are linear, smooth and gradual.

Scientists have uncovered a fascinating new insight into what caused one of the most rapid and dramatic instances of climate change in the history of the Earth.

Depuis 30 ans, la compréhension du climat terrestre dans sa globalité s’est donc terriblement améliorée, permettant le développement de nouveaux concepts. L’un d’entre eux suscite beaucoup d’intérêt auprès de la communauté scientifique : c’est celui des points de basculement (tipping point).

On les appelle les "tipping points" ; les points de rupture. A partir d'eux, le climat change de manière radicale et irréversible. Des événements considérés comme des points de rupture sont la fonte des glace rapide au Groenland, qui fait monter le niveau des eaux, le fait que la forêt amazonienne rejette plus de CO2 qu'elle n'en absorbe, et les canicules en Sibérie qui ont fait fondre le sol gelé (pergélisol), ce qui a fait relâcher d'énormes quantités de méthane dans l'air. Un effondrement du Gulf Stream serait également un point de rupture absolument catastrophique.

Climate scientists have detected warning signs of the collapse of the Gulf Stream, one of the planet’s main potential tipping points. The research found “an almost complete loss of stability over the last century” of the currents that researchers call the Atlantic Meridional Overturning Circulation (AMOC). The currents are already at their slowest point in at least 1,600 years, but the new analysis shows they may be nearing a shutdown.

Abrupt disruptions to Earth's climate thousands of years ago that caused extreme sea-level rise and mass ice cap melting can serve as an early warning system for today's planetary tipping points, according to new research.

Around 13,000 researchers have called for urgent action to slow down the climate emergency as extreme weather patterns shock the world. They listed three core measures.